The disclosures of Japanese Patent Application Nos. HEI 11-132133 filed on May 13, 1999 and HEI 11-191716 filed on Jul. 6, 1999, including their specifications, drawings and abstracts are incorporated herein by reference in their entireties.
1. Field of Invention
The present invention relates to a wire winder and to a wire winding method for forming a coil by winding a conductive wire around a winding frame that is being rotated and, more particularly, to a wire winder and to a wire winding method capable of reliably defining a winding position of a conductive wire while requiring merely a simple apparatus construction. The invention also relates to a coil formed by the wire winding method.
2. Description of Related Art
In rotating electric devices, such as electric motors, generators, and the like, the number of turns of coil winding is often increased in order to increase the power output. However, a simple increase in the number of turns of coil winding results in an enlarged size of the rotating electric device. In order to avoid such a device size increase, it is a normal practice to increase the proportion of the total sectional area of the windings of a coil to the sectional area of a slot that houses the coil (hereinafter, referred to as xe2x80x9cspace factorxe2x80x9d). The space factor can be increased by winding a conductive wire in good arrangement without leaving a gap. Coil forming methods and coil forming apparatus for winding a conductive wire in good alignment have been developed. Such a related apparatus is described in Japanese Patent Application Laid-Open No. HEI 7-183152.
To increase the space factor, the use of a rectangular conductive wire is effective. The rectangular conductive wire refers to a conductive wire having a generally rectangular or quadrangular sectional shape. The use of a rectangular wire further reduces gaps between windings of a coil, compared with the use of a wire having a circular sectional shape.
A coil with an increased space factor is typically formed by winding a conductive wire on a magnetic pole of a rotating electric device or a winding frame (core) having a shape corresponding to that of the magnetic pole in a manner of one turn at a time without leaving a gap between adjacent windings. After the wire is wound over the entire length of the coil and therefore forms a single complete winding layer, the wire is wound for the next layer over the completed layer in the same manner. In this manner, a predetermined number of winding layers are formed.
During the above-described wire winding process for forming a coil, if a positional deviation of the conductive wire occurs at the time of a turn shift, that is, a shift of the wire from one turn to the next, the shape precision of the coil degrades. If the amount of deviation of the wire increases, the number of turns of the wire in a layer will decrease.
In order to avoid such an undesired event, it is necessary to prevent a positional deviation of the wire at the time of a turn shift. For example, in Japanese Patent Application Laid-Open No. HEI 11-13051, a turn shift portion shaper unit is provided. This unit press-forms the wire to form an S-shaped turn shift portion before that portion of the wire is wound on a winding frame.
However, if the winding frame is frequently stopped in order to prevent wire deviation, the productivity of coils decreases. Therefore, it is desirable to prevent wire deviation without stopping the winding frame. To that end, it may be conceivable to rotate a wire deviation preventing unit synchronously with the winding frame. However, this technology has a drawback of increasing the size of a rotating portion of a wire winding apparatus. In particular, since an actuator for operating the unit is rotated together with the winding frame, the apparatus construction becomes complicated, and the load on a motor for rotating the winding frame increases.
Accordingly, it is an object of the invention to provide a wire winder and a wire winding method capable of preventing deviation of the winding position of a conductive wire during continuous rotation of a winding frame while employing a simple apparatus construction.
In accordance with one aspect of the invention, a wire winder for forming a coil by winding a conductive wire includes a winding frame around which the conductive wire is wound while the winding frame is being rotated. Additionally, a guide mechanism contacts the conductive wire wound around the winding frame and defines a winding position of the conductive wire. A guide support link mechanism is provided coaxially with a rotational axis of the winding frame so as to rotate synchronously with the winding frame. The guide support link mechanism supports the guide mechanism. A link driver is provided to move an element member of the guide support link mechanism in a direction of the rotational axis of the winding frame without rotating together with the winding frame and the guide support link mechanism. The guide support link mechanism converts a movement provided in the direction of the rotational axis of the winding frame by the link driver into a movement of the guide mechanism in a direction of a diameter of the winding frame.
In the above-described wire winder, the guide mechanism defines the winding position of the conductive wire by contacting the conductive wire, so that positional deviation of the conductive wire is prevented. Furthermore, the guide mechanism is supported by the link mechanism, which synchronously rotates with the winding frame. Therefore, the guide mechanism is able to function even while the winding frame is rotating.
In this embodiment of the invention, the link mechanism is designed to convert a movement in the direction of the rotational axis of the winding frame into a movement of the guide mechanism in the direction of the diameter of the winding frame. Therefore, the link driver merely needs to provide the link mechanism with a movement in the direction of the rotational axis. That is, the link driver can perform its function without needing to rotate together with the winding frame. For example, an actuator fixed to an apparatus table or the like will easily apply a force to a link that is rotating. Since the actuator does not need to rotate together with winding frame, the apparatus construction is simplified and the load on a winding frame-rotating motor can be reduced.
In the wire winding method of this embodiment of the invention, the conductive wire wound around the winding frame is contacted with a guide mechanism that defines a winding position of the conductive wire. The guide mechanism supported with a guide support link mechanism that is provided coaxially with the rotational axis so as to rotate synchronously with the winding frame. A link driver that does not rotate about the rotational axis together with either one of the winding frame and the guide support link mechanism is utilized to move a member of the guide support link mechanism in a direction of the rotational axis. The guide support link mechanism converting a movement in the direction of the rotational axis provided by the link driver into a movement of the guide mechanism in a direction of a diameter of the winding frame.
In an embodiment of the wire winding method of the invention, the winding position of a conductive wire is defined by the guide mechanism that contact opposite sides of the conductive wire at sites forward and rearward of a turn shift portion, so that positional deviation of the conductive wire is prevented. The four guide members comprising the guide mechanism can be driven independently of one another. Even where coils to be formed have different shapes of turn shift portions, the four guide members can be used to define the winding position of the conductive wire for the production of each coil. Thus, it becomes unnecessary to replace the guide members, so that productivity improves.
According to an aspect of the invention, it is not necessary that all the four guide members simultaneously contact a conductive wire. That is, the guide members may also be driven so that one or more of the guide members contact the conductive wire and the other guide members do not contact the conductive wire but are withdrawn therefrom as needed.